Mitsubishi Electric FX2N Beginners Manual page 61

An Introduction to Programming
b Switching the motor off with the limit switches
Ladder Diagram
X003
27
X006
29
When the gate is open limit switch S3 is activated and input X3 is switched off. This resets relay
M1, turning off the motor. When the gate is fully closed S6 is activated, X6 is switched off and
M2 is reset, turning off the motor. For safety reasons the limit switches are break contacts. This
ensures that the motor is also switched off automatically (or cannot be switched on) if the con-
nection between the switch and the input is interrupted.
NOTE The limit switches must be wired so that they also switch off the motor automatically without
support from the PLC (see wiring diagram).
b Controlling the motor
Ladder Diagram
M1
31
M2
33
At the end of the program the signal states of relays M1 and M2 are transferred to outputs Y001
and Y002.
b Warning lamp: "Gate in Motion" and "Gate in Undefined Position"
Ladder Diagram
X003 X006 M8013
35
If neither of the limit switches is activated this means that the gate is being opened or closed or
has been stopped in an intermediate position. In all these situations the warning lamp blinks.
The blink speed is controlled with special relay M8013, which is automatically set and reset at
1s intervals (see Chapter 4.2).
FX Beginners Manual
Programming PLC Applications
RST M1
RST M2
Y001
Y002
Y000
Instruction List
27 LDI X003
28 RST M1
29 LDI X006
30 RST M2
Instruction List
31 LD M1
32 OUT Y001
33 LD M2
34 OUT Y002
Instruction List
35 LD X003
36 AND X006
37 AND M8013
38 OUT Y000
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